Fluid driving device for actuating mechanisms having an initial idle stroke



2 Sheets-Sheet l e. HOUPLAIN Filed April 7. 1930 FLUID DRIVING DEVICEFOR ACTUATING MECHANISMS HAVING AN INITIAL IDLE STROKE "H. Q 5;: giii Mfin .3 E w a g Q Jamaal-1932.

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FLUID DRIVING DEVICE FOR ACTUATING MECHANISMS HAVING AN INITIAL IDLESTROKE Filed April '7, 1950 2 Sheets-Sheet 2 rm 7 I Patented June 28,1932 UNITED STATES PATENT OFFICE cnozaens nournam, or minis; gamma,ASSIGNOR '10 soc'IE'rE mzs raisins HOUPLAIN,

' or rams, mmncn FLUID DRIVING DEVICE FOR ACTUATING MECHANISMS HAVING ANINITIAL IDLE STROKE Application filed April 7, 1930, Serial No. 442,438,and in France November 2, 1929.

which a variable play may take place, be-

cause of wear for instance. According to the invention said apparatus 1scaused to effectively work only after a more or less important idlecourse, and after the entire play has been taken up; said apparatus isso devised that the consumption of driving fluid is as much as possibleindependent of said idle course in order to reduce the consumptionofdriving energy, when the latter is supplied by a compressor and storedin the form of compressed air in a tank, or the amplitude of themovement required from the operator when he acts upon a hand or footcontrol.

For that purpose, the device comprises a fixed cylinder of largediameter. a piston sliding in this cylinder and intended .to beconnected to the apparatus to be driven, a movable cylinder'ofsmalldiameter, rigid with the large piston and having one of its endsopen, a small piston sliding in thismovable cylinder,'springs pushingthe small and the large pistons respectively towards the open end of thesmall cylinder and-'towardsthe corresponding bottom of the largecylinder,

this bottom having an'opening for the admission and issue of .thedriving fluid, the open end of the small cylinder being adapted to fitin a'fluid-tight manner on the bottom of the largecylinder about thesaidopening, and ratchetmeans through which the large piston drives thesmall piston when it moves away from the said bottom of the largecylinder, but is not-driven in the said direction by the small piston.

With such adevice, the quantity of fluid for moving the smallpiston-is-always small whatever may be the length of the idle stroke dueto the play of the apparatus to be driven,

and the consumption of fluid for moving the large piston and producingthe real effective work is not materially increased owing to this idlestroke.

Two forms of carrying out the subject-matter of the invention will bedescribed, by way of example only, with reference to the accompanyingdrawings, in which:

Fig. 3 is a section, on an enlargedscale, of

the details of Fig. 1.

Fig. 4 is a view similar to Fig. 3 showing a modification.

Fig. 5 is a longitudinal section diagrammatically illustrating a controldevice for the brakes of motor cars.

Referring to Figs. 1 to 3, the brake cylinder 1 communicates with thesupply of compressed air through the orifice 2; to the main piston 3 issecured an auxiliary cylinder 1, of small diameter, provided with anorifice 5 arranged opposite the orifice 2; a spring 6 pushes back thepiston 3 so as to press the end of the cylinder 4. upon a seat 7surrounding the orifice 2 and to thus prevent compressed air fromentering the space 8 of the brake cylinder 1. A piston 9 can slide inthe aux iliary cylinder 4 in 0 position to the action of a springlO. Ontlle piston rod 11 is secured a fiat member 12 provided with teeth 13capable of gearing with the corresponding teeth 14 of'levers or pawls 15which are pivoted at 16 on the cylinder 4 and constantlypulled towardseach other by springs. 18.

The rod 11 terminates in a small cross head 17 serving to actuate thecontrol lever ofv the brake rigging. The levers 15 press, "through theirend 20, upon inclines 21 integral with thecylinder 1 when the auxiliarycylinder 4 rigid with the piston 3 is in the position of rest, so thattheir teeth 14 are then released from theteeth 13 of the member 12 (Fig.1). As soon as the piston 3 moves forward, driving the auxiliarycylinder t and the levers 15, the latter will be released from theinclines 21 and will come in engagement with the teeth of the member 12which they will then rigidly drive.

A channel 22 causes the inner space 23 of the auxiliary cylinder 4 andthe inner space 8 The operation is as follows: The compressed airente'rs through the orifices 2 and 5, acts-upon the piston 9 which,through its rod 11, member 12 and cross head 17, acruates the brakerigging and brings the brake shoes in contact with the wheels. \Vhen thepiston 9 has passed the orifice of the channel 22, the compressed airpasses through the latter, from the chamber 23 of the cylinder 4 to thechamber 8 of the brake cylinder; when the pressure in this chamber 8 issuflicient, the brake piston 3 moves away from the seat 7; the piston 3,by moving forward, drives the auxiliary cylinder 4 and the levers 15mounted on the latter, and these levers, the ends 20 of which remainreleased from the inclines 21, continue to actuate the member 12, therod 11 and, consequently, the brake rigging. The compressed air thenhaving moreover a free passage between the piston 3 and the seat 7,directly acts on this piston and the braking action takes place in theor- Cil dinary manner.

For releasing the brakes, the compressed air is exhausted from thechamber 8 and the piston 3 comes back to its position of rest under theaction of the spring 6 driving the auxiliary cylinder and the entirebrake rigging; the ends 20 of the levers 15 come in engagement with theinclines 21, so that these levers are released from the teeth 13 of themember 12. The spring 10 then brings back the piston 9 to its originalposition.

It is to be understood that this example of carrying out thesubject-matter of the invention has been given simply by way of exampleand not in a limiting sense, and that modifications of detail can beeffected without departing thereby from the principle of the presentinvention.

Thus as shown in Fig. 4, the communication between the chamber 23 of theauxiliary cylinder 4 and the chamber 8 of the brake cylinder 1 couldalso take place through opening of a small spring valve 25 mounted onthe bottom of the cylinder 4 and opening only when the pressure in thiscylinder would have sufficiently increased for moving the piston 9 andbringing the brake shoes in contact with the wheels.

In order to be sure that the auxiliary piston should move backwards onlywhen the main piston will already have returned to its startingposition, that is to say. that the levers 15 will have been releasedfrom the teeth 13 of the member 12, a valve 24 (Fig. 4) placed on theorifice 5 will allow compressed air to enter the chamber 23 of theauxiliary cylinder and will prevent it from issuing therefrom. The rodof this valve can be provided with an extension which will tit upon theseat 7 when the main piston 2 will have mturned backwards, which willcause the said valve to open and will then allow the return of theauxiliary piston.

The apparatus illustrated in Fig. 5 and adapted to actuate the brakes ofa motor car, comprises a fixed cylinder 1', of large diameter, in whichslides a piston 3 rigid with a movable cylinder 4, of small diameter,the open end 5 of which presses under the action of a powerful spring6', against a seat 7 provided on the bottom 1!! of the cylinder 1' aboutthe inlet and outlet opening 2' for the fluid under pressure.

In the cylinder slides a piston 9, the rod 11 of which is adapted to beconnected to the brake rigging; this piston is pushed towards the end 5by a light spring 10 hearing on a bottom 4a of the cylinder 4, thisbottom serving at the same time to guide the rod 11.

()n the latter is frictionally mounted a flange 31 provided withrecesses in which are arranged balls 32, adapted to cooperate with aconical surface 33 provided in the cylinder 4 for actuating the rod 11'through the cylinder 4' in the direction of the arrow 7'. Moreover, theflange 31 has a circular shoulder 34 adapted to cooperate with a cap 35secured on the cylinder 4' for serving to actuate the flange through thecylindcr in a direction reverse. to that indicated by the arrow f.Finally, springs 36 are secured on the flange 31 andarranged forabutting against a J.

fixed abutment 37, in order to retain the flange and to prevent theballs from wedging against the conical surface 33 when the rod 11returns in the direction reverse to the arrow f, and tends to drive theflange 31by friction.

In this form of construction, the driving fluid is oil enclosed in thespace comprised. on the one hand, between the bottom 1 1. of

the large cylinder and the pistons 3 and 9, s

and, on the other hand, in the space comprised between the bottom lrzand a piston 38 sliding in a cylinder 39 rigid with the said bottom. Therod of the piston 38 is connected to a control pedal 40.

The bottom 1a of the large cylinder is further provided. besides theseat 7, with an opening 41 which is normally closed by a valve 42-arranged for opening inwardly of the cylinder 1 in opposition to theaction of a returning spring :43.

The operation is as follows:

At rest, the springs 6' and 10' hold the pistons 3 and 9 in the positionillustrated; the brakes are released.

When the driver presses upon the pedal 40, the piston 38 forces the oilof the cylinder 39 through the opening 2. and the pressure of this oilon the piston 9 has for eflcct to push back the latter with the rod 11.thus compressing the light spring 10' and driving the brake riggingwhich opposes but a small resistance until all the play is taken up. Atthis moment, the resistance suddenly increases and the thrust of thepiston 38 on the oil continuing, an over pressure of the oil resultstherefrom. which causes the opening of the valve 42; the pressure ofthe'oil then acts both on the piston 9 and the piston 3, and compels thelatter'to move forward, with the cylinder 4, in the direction of thearrow 7. The conical surface 33 immediately comes in engagement with theballs 32, and the latter, wedged between this surface and the rod 11,drive the said rod, determining, consequently, the application of thebrakes. The braking power which can thus be obtained depends on theratio of the diameters of the cylinder 1 and of the cylinder 39, ratiowhich can be chosen as large as desirable.

On the other hand, the initial displacement of the piston 38, serving topush back the piston 9' until the entire play is taken up, depends onthe ratio of the diameters of the cylinder 39 and cylinder 4', and thisratio can be so chosen as to render this initial displacement as smallas desirable.

When the operator allows the pedal 40 to come back, the springs-6 and10' act for returning the members to their initial position: the piston3' is first returned by the action of the spring 6, with the cylinder4'; the cap 35 draws the flange 31 along with it, and the piston 9 isreturned through. the medium of the spring 10 with a certain lag byreturning the brake rigging to the position of rest. 'When the cylinder4' has come back to the position of rest, the springs 36 pressed againstthe abutment 37, retain the flange 31 in opposition to the frictionaldriving stress resulting from the continuation of the return movement ofthe rod 11, so that the balls 32 do not wedge against the surface 33 anddo not prevent this return movement.

Such a device is capable of receiving multiple applications and, amongothers, it can be used as a brake control device; it can serve toconstitute a jack, the platform of which will first rapidly come underthe load to be lifted, the lifting strain taking place but subsequently;finally, it can be used every time the apparatus to be driven gives riseto an idle stroke or to a small resistance before opposing a greatresistance.

The device in accordance with the invention is applicable quite as well,with modifications of detail, to vacuum brakes, and to all kinds ofbrakes actuated by a fluid. 7

I claim: H

1. Fluid driving device, comprising a fixed cylinder of large diameter,a piston sliding in this cylinder, a movable cylinder of small diameter,rigid with the said piston and having one of its ends open, asmallpiston sliding in this movable cylinder and adapted to be connected tothe apparatus to be driven, springs pushing the small and the largepistons respectively towards the open end of the small cylinderjandtowards the corresponding bottom of the large cylinder, this bottomhaving an opening for the admission and issue of the driving fluid, theopen end-of the small cylinder being adapted to fit in a fluid-tightmanner on the bottom of the large cylinder.

about the said opening, and ratchet means through which the large pistondrives the small piston when it moves away from the said bottom of thelarge cylinder, and-a spring valve for the admission of the drivingfluid,

this valve opening within the large cylinder outside of the bearingzoneof the small cylinder on the bottom of the large cylinder.

2. Fluid driving device, comprising a fixed cylinder of large diameter,a piston sliding in this cylinder, a movable cylinder of small diameter,rigid with the said piston and having one of its ends open, a smallpiston sliding in this movable cylinder and adapted to of the smallcylinder being adapted to fit in r a fluid-tight manner on the bottom ofthe large cylinder about the said opening, ratchet means through whichthe large piston drives the small piston when it moves away from thesaid bottom of the large cylinder, a fixed cylinder having anintermediate diameter between those of the two first cylinders andcommunicating with the said opening of the first-mentioned cylinder, apiston in this cylinder of intermediate diameter, and foot control meansfor moving the last-mentioned piston.

3. Fluid driving device, comprising a fixed cylinder of large diameter,a piston sliding in this cylinder, a movable cylinder of small diameter,rigid with said piston, a small piston sliding in. this movable cylinderand adapted to be connected to the apparatus to be driven, the cylinderof small diameter and that of large diameter being each provided with anorifice for the admission of the driving fluid, a spring valve forclosing the orifice of the large cylinder and ratchet means throughwhich the large piston drives the small piston as soon as it moves awayfrom the bottom of the large cylinder.

4. Fluid driving device, comprising a fixed cylinder of large diameter,a piston sliding in this cylinder, a movable cylinder of small diameter,rigid with said piston, a small piston sliding in this movable cylinderand adapted to be connected to the apparatus to be driven, the cylinderof small diameter and that of large diameter being each provided with anorifice for the admission of the driving fluid, a spring valve forclosing the orifice of the large cylinder, and. ratchet means throughwhich the large piston drives the small piston as soon as the same movesaway from the bottom of the large cylinder, these ratchet meanscomprising a rod rigid with the small piston, a flange frictionallymounted on the said rod, abutments limiting the movements of the saidflange relatively to the said small cylinder, balls maintained in thesaid flange against the rod rigid with the small piston, the smallcylinder having a conical surface adapted to engage the said balls andto press them against the said rod as soon as the small cylinder movesaway from the bottom of the large cylinder.

5. Fluid driving device comprising a fixed cylinder of large diameter, apiston sliding in this cylinder, a movable cylinder of small diameterrigid with said piston, a small piston sliding in this movable cylinderand adapted to be connected to the apparatus to be driven, the cylinderof small diameter and that of large diameter being each provided with anorifice for the admission of the driving fluid, a spring valve adaptedto close the orifice of the large cylinder and ratchet means throughwhich the large piston drives the small piston as soon as the same movesaway from the bottom of the large cylinder, these ratchet meanscomprising a rod rigid with the small piston, a flange frictionallymounted on the said rod, abutments limiting the movements of the saidflange relatively to the said small cylinder, balls maintained in thesaid flange against the rod rigid with the small piston, the smallcylinder having a conical surface adapted to engage the said balls andto press them against the said rod as soon as the small cylinder movesaway from the bottom of the large cylinder and means for disengagingthem when the large piston has reassumed its starting position.

In testimony whereof I have hereunto affixed my signature.

GEORGES HOUPLAIN.

